Theorem bnj873 34947

Description: Technical lemma for bnj69 35033. This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) (New usage is discouraged.)

Hypotheses

Ref	Expression
bnj873.4	⊢ 𝐵 = {𝑓 ∣ ∃𝑛 ∈ 𝐷 (𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓)}
bnj873.7	⊢ (𝜑′ ↔ [𝑔 / 𝑓]𝜑)
bnj873.8	⊢ (𝜓′ ↔ [𝑔 / 𝑓]𝜓)

Assertion

Ref	Expression
bnj873	⊢ 𝐵 = {𝑔 ∣ ∃𝑛 ∈ 𝐷 (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)}

Distinct variable groups:   𝐷,𝑓,𝑔   𝑓,𝑛,𝑔   𝜑,𝑔   𝜓,𝑔

Allowed substitution hints:   𝜑(𝑓,𝑛)   𝜓(𝑓,𝑛)   𝐵(𝑓,𝑔,𝑛)   𝐷(𝑛)   𝜑′(𝑓,𝑔,𝑛)   𝜓′(𝑓,𝑔,𝑛)

Proof of Theorem bnj873

Step	Hyp	Ref	Expression
1		bnj873.4	. 2 ⊢ 𝐵 = {𝑓 ∣ ∃𝑛 ∈ 𝐷 (𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓)}
2		nfv 1915	. . 3 ⊢ Ⅎ𝑔∃𝑛 ∈ 𝐷 (𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓)
3		nfcv 2896	. . . 4 ⊢ Ⅎ𝑓𝐷
4		nfv 1915	. . . . 5 ⊢ Ⅎ𝑓 𝑔 Fn 𝑛
5		bnj873.7	. . . . . 6 ⊢ (𝜑′ ↔ [𝑔 / 𝑓]𝜑)
6		nfsbc1v 3758	. . . . . 6 ⊢ Ⅎ𝑓[𝑔 / 𝑓]𝜑
7	5, 6	nfxfr 1854	. . . . 5 ⊢ Ⅎ𝑓𝜑′
8		bnj873.8	. . . . . 6 ⊢ (𝜓′ ↔ [𝑔 / 𝑓]𝜓)
9		nfsbc1v 3758	. . . . . 6 ⊢ Ⅎ𝑓[𝑔 / 𝑓]𝜓
10	8, 9	nfxfr 1854	. . . . 5 ⊢ Ⅎ𝑓𝜓′
11	4, 7, 10	nf3an 1902	. . . 4 ⊢ Ⅎ𝑓(𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)
12	3, 11	nfrexw 3282	. . 3 ⊢ Ⅎ𝑓∃𝑛 ∈ 𝐷 (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)
13		fneq1 6580	. . . . 5 ⊢ (𝑓 = 𝑔 → (𝑓 Fn 𝑛 ↔ 𝑔 Fn 𝑛))
14		sbceq1a 3749	. . . . . 6 ⊢ (𝑓 = 𝑔 → (𝜑 ↔ [𝑔 / 𝑓]𝜑))
15	14, 5	bitr4di 289	. . . . 5 ⊢ (𝑓 = 𝑔 → (𝜑 ↔ 𝜑′))
16		sbceq1a 3749	. . . . . 6 ⊢ (𝑓 = 𝑔 → (𝜓 ↔ [𝑔 / 𝑓]𝜓))
17	16, 8	bitr4di 289	. . . . 5 ⊢ (𝑓 = 𝑔 → (𝜓 ↔ 𝜓′))
18	13, 15, 17	3anbi123d 1438	. . . 4 ⊢ (𝑓 = 𝑔 → ((𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓) ↔ (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)))
19	18	rexbidv 3158	. . 3 ⊢ (𝑓 = 𝑔 → (∃𝑛 ∈ 𝐷 (𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓) ↔ ∃𝑛 ∈ 𝐷 (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)))
20	2, 12, 19	cbvabw 2804	. 2 ⊢ {𝑓 ∣ ∃𝑛 ∈ 𝐷 (𝑓 Fn 𝑛 ∧ 𝜑 ∧ 𝜓)} = {𝑔 ∣ ∃𝑛 ∈ 𝐷 (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)}
21	1, 20	eqtri 2756	1 ⊢ 𝐵 = {𝑔 ∣ ∃𝑛 ∈ 𝐷 (𝑔 Fn 𝑛 ∧ 𝜑′ ∧ 𝜓′)}

Syntax hints:   ↔ wb 206   ∧ w3a 1086   = wceq 1541  {cab 2711  ∃wrex 3058  [wsbc 3738   Fn wfn 6484

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2115  ax-9 2123  ax-10 2146  ax-11 2162  ax-12 2182  ax-ext 2705

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1544  df-fal 1554  df-ex 1781  df-nf 1785  df-sb 2068  df-clab 2712  df-cleq 2725  df-clel 2808  df-nfc 2883  df-ral 3050  df-rex 3059  df-rab 3398  df-v 3440  df-sbc 3739  df-dif 3902  df-un 3904  df-ss 3916  df-nul 4285  df-if 4477  df-sn 4578  df-pr 4580  df-op 4584  df-br 5096  df-opab 5158  df-rel 5628  df-cnv 5629  df-co 5630  df-dm 5631  df-fun 6491  df-fn 6492

This theorem is referenced by:  bnj849  34948  bnj893  34951